"Li staras malproksime de ni."
Translation:He is standing far from us.
What is the difference between this and 'Li staras malproksima de ni'?
Are you sure anybody says "staras malproksima"?
If you remember School House Rock (Lolly Lolly Lolly) - you're either older, or found it on YouTube ... and:
How, where, or when, condition or reason, these questions are answered - when you use an adverb."
So, "malproksime" says where he's standing. You'd use "malproksima" to describe something which is far away. A distant land, a distant place, a distant friend....